Electrosynthesis of hydrogen peroxide using gas diffusion electrodes (GDEs) modified with nanostructured electrocatalysts and their application in the degradation of polluting organic compounds

• Grant number: 24/11170-9
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: September 01, 2024
• End date: June 30, 2029
• Field of knowledge: Engineering - Sanitary Engineering - Water Supply and Wastewater Treatment
• Principal Investigator: Marcos Roberto de Vasconcelos Lanza
• Grantee: Oswaldo Costa Junior
• Host Institution: Instituto de Química de São Carlos (IQSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
• Associated research grant: 22/12895-1 - Advanced processes for the degradation of emerging pollutants: catalytic materials, electroanalytical sensors and scientific dissemination, AP.TEM

Abstract

The oxygen reduction reaction (ORR) for the electrogeneration of hydrogen peroxide (H2O2) has been the focus of electrochemical research for years due to the widespread use of this compound as an oxidizing agent in various procedures, given its high reduction potential of +1.77 V. However, the use of RRO processes remains a challenge due to their kinetic complexity and high energy demand, leading to high operating costs. In order to overcome these disadvantages, there is a need to study the influence of new electrocatalyst materials for use in these processes, in order to make the procedure economically viable, reducing costs and increasing the selectivity of H2O2 electrogeneration. To this end, this project proposes the synthesis of new iron sulphide (Fe3S4) nanoparticles, modified with zinc (Zn), manganese (Mn) and tungsten (W), in the Core-Shell type, anchored to the surface of Printex L6 carbon (CPL6) for application as electrocatalysts in the RRO process for the production of H2O2 in situ and the degradation of antibiotics from the macrolide class. Initially, the electrochemical behavior of the material will be evaluated in a ring-rotating disk electrode (RDDE) system, the Ag|AgCl reference electrode and platinum counter electrode, in a support electrolyte of 0.1 mol L-1 K2SO4 solution in acidic (pH 3.0) and alkaline (pH 9.0) media. In the RRDE, the synthesized nanomaterials will be deposited forming a microlayer. The materials will also be characterized structurally and morphologically using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning and transmission electron microscopy (SEM and TEM) techniques. Subsequently, these electrocatalysts will be evaluated using the gas diffusion electrode (GDE) made with carbon fabric, CPL6 and the NPs proposed in this project, in order to quantify H2O2 electrogeneration, as well as evaluating the parameters that most influence this process, such as pH and applied current density. Finally, the optimized system will be applied and studied for the degradation of antibiotics from the macrolide class (azithromycin and erythromycin, for example) through photo-electrochemical processes.